title: A simplified breath-holding method for measuring oxygenated mixed venous carbon dioxide pressure.
abstract: We have attempted to simplify the breath-holding method for measuring mixed venous PCO2 by the use of a single breath of 100% O2. This method is based on analysis of partial pressures of CO2 in three samples of alveolar gas obtained at 5, 10, and 15 sec of breath-holding after inspiration of 100% oxygen. Assuming exponential build-up of CO2 in alveolar gas, oxygenated mixed venous PCO2 can then be determined. Results in 35 subjects were compared with those of the previously reported breath-holding method for estimating oxygenated mixed venous PCO2 based on inspiring two gas mixtures; correlation coefficient was found to be 0.92. In 17 patients, samples of blood were obtained from the pulmonary artery by percutaneous catheterization; measured values in blood correlated well with the oxygenated non-invasively determined values (r = 0.83).
mesh_terms: D001784:Blood Gas Analysis / Q000379:methods; D001790:Blood Physiological Phenomena; D002245:Carbon Dioxide; D006801:Humans; D010100:Oxygen; D010313:Partial Pressure; D011651:Pulmonary Artery / Q000502:physiology; D014680:Veins / Q000502:physiology
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen